Gasa-do is located in Jindo-gun, Jeollanam-do, South Korea and there are about 170 households. Gasa-do were selected as an energy-independent island project in 2012 and promoted as a demonstration complex for the energy-independent island by the government of Republic of Korea and the Korea Electric Power Corporation.
There are more than 170 households and 290 inhabitants, and the daily average load is 95kW. Three 100kW diesel generators were used. The following facilities were constructed as a demonstration project for energy independent island.
- Two 500kW PCSs and one 250kW PCS
- Littium-ion battery ESS 3MWh
- Four 100kW WTs
- PV 314kW
- Three 100kW diesel generators
The ESS is installed at 3MWh level and is designed to be able to handle the load of the day island without operating the diesel generator at 100% charge. Some of the PV generators were installed on the water to minimize installation space. In Gasa-do, the average wind speed is 5.8m/s and the average solar radiation is 3.88kWh/㎡. When the solar radiation and wind speed are enough, it is possible to supply electricity only by renewable power generation. If the renewable power generation is higher than the power consumption, surplus power is used to charge the ESS. Water tank and air conditioner loads were used for demand management and were directly controlled by considering renewable energy output and battery SOC.
By constructing such a microgrid, annual electricity generation fuel costs could be reduced by about 320 million won, which is about half of what was used in the past.
※ This usecase is written based on the article in http://www.kea.kr/elec_journal/2015_7/12.pdf